This invention relates to a storage-stable transdermal adhesive bandage structure for the administration of medicinal substances by means of a patch through the skin of patients.
Medicinal formulations in transdermal dosage forms (patches) must be sealed in a vapor tight manner for storage, if they need protection from air or moisture, or if they contain volatile ingredients. In the latter case, the seal must also isolate the formulation from the adhesive which is meant to secure the patch to the skin. The vapor tight seal in all commercial patches consists of sheets of aluminum foil film laminates, because plastic films without aluminum foil are not sufficiently impermeable to vapors. Typically, the formulation is enclosed between two sheets of such aluminum foil laminates, heat-sealed together. One of these sheets then remains on the patch which is worn by the patient. Aluminum foil worn in transdermal patches has drawbacks: it renders the patch opaque and esthetically unpleasing, it presents a hazard when exposed to high electric potentials or microwave radiation, and it has caused skin irritation.
It is the object of the invention to construct a transdermal dosage form, where the formulation portion is completely sealed between sheets of aluminum foil film laminates during storage, but contains no aluminum foil in the patch when worn by the patient.